Block Reference

"Defines a field type Block reference which allows the block to be displayed as the content of the field." Alternately, if the bean module is enabled, blocks can be referenced using the entity reference module instead.

Title

This module, in a basic sense, allows the title to be an actual Drupal field. This comes in especially handy when doing translations, as titles are not translatable in core.

Understanding Panels styles

It's hard to find really good documentation on creating custom ctools style plugins, like the stylizer that comes bundled with panels. For example, if you search the web, you'll come up finding a link to http://dustinbons.com/panels-styles-plugin-drupal-7 which is not really a very good tutorial. If you view the advanced help module page on this, it comes up blank.

Panels

A feature packed layout tool that grows on you. Used by many many websites.

Panels Everywhere

Let panels take over the whole page. From d.o:
"Panels Everywhere is an advanced method to completely do away with Drupal's restrictive blocks system and instead use the much more freeing Panels Layout system to control how your pages look. Panels Everywhere modifies the page as it is being rendered to 'wrap' the content in a display and can even take over your page theme to do away with the need for a page.tpl.php."